Accurate Axillary Nodal Staging Can be Achieved after Neoadjuvant Therapy for Locally Advanced Breast Cancer

Abstract

Lymph node status remains the most important prognostic indicator for breast cancer. Recent reports have established that the accuracy of assessing lymph node status is proportional to the number of nodes dissected. The accuracy of axillary staging following neoadjuvant chemotherapy has been cited as a technical concern due to limited node retrieval. The current study attempts to evaluate the ability to perform sentinel node biopsy (SNB) and formal axillary node dissection (AND) following neoadjuvant chemotherapy and to compare these results with non-neoadjuvant patients. One hundred sixteen consecutive patients undergoing SNB with simultaneous AND were retrospectively reviewed. Forty-two of these patients were treated with neoadjuvant chemotherapy prior to AND. Overall success rate in performing SNB in the neoadjuvant group was 95 per cent, and no false negatives have been noted to date. The overall SNB success rate in the non-neoadjuvant group was also 95 per cent with a false negative rate of 3 per cent. After AND in each group, a mean of 21 nodes were retrieved in the neoadjuvant group and 17.9 nodes in the non-neoadjuvant group (P = 0.018). In the neoadjuvant group, there were 19 node positive patients (42%) and 21 patients (28%) in the non-neoadjuvant group (P = 0.16). The mean number of positive nodes per patient was also similar between the two groups (2.9 in the neoadjuvant group vs 1.67 in the non-neoadjuvant group, P = 0.10). Following neoadjuvant therapy, accurate evaluation of the axilla is feasible. In this study, the mean number of nodes is significantly different in favor of the neoadjuvant group, but there is no significant difference in the number of node positive patients identified or in the mean number of positive nodes identified per patient. SNB is technically feasible with accuracy similar to that seen in patients with no history of neoadjuvant therapy. Neoadjuvant chemotherapy extends the use of breast-conserving therapy without sacrificing the ability to accurately stage the axilla either by use of standard axillary dissection or SNB.